Wednesday, 10 May 2017

Ocean Currents of the World

Major Ocean Currents

»The water on the surface of the oceans is constantly flowing in one direction from one place to another. These flowing movements of water in oceans are called ocean currents.

»Ocean current,stream made up of horizontal and vertical components of the circulation system ofoceanwaters that is produced by gravity, windfriction, and waterdensityvariation in different parts of the ocean.

»The current's direction and speed depend on theshorelineand the ocean floor. They can flow for thousands of miles and are found in all the major oceans of the world.

»Ocean currents are similar towindsin theatmospherein that they transfer significant amounts ofheatfromEarth’sequatorial areas to the poles and thus play important roles in determining theclimatesof coastal regions.

»Ocean currents flow for great distances, and together, create theglobal conveyor beltwhich plays a dominant role in determining theclimateof many of theEarth’s regions.

»More specifically, ocean currents influence the temperature of the regions through which they travel.

»For example, warm currents travelling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them.

»Perhaps the most striking example is theGulf Stream, which makesnorth-west Europemuch moretemperatethan any other region at the samelatitude.

»Another example isLima, Peruwhere the climate is cooler (sub-tropical) than the tropical latitudes in which the area is located, due to the effect of theHumboldt Current.

Based on their depththe ocean currents can also be divided into two categories:

·Ocean currents can be found on the water surface and deeper down.

·Currents on the surface often depend on the wind. They travel clockwise in the northern hemisphere. They travel counterclockwise in the southern hemisphere. They are found up to 400 metres (1,300 ft) below the surface of the ocean.

·Deeper currents depend on water pressure, temperature, and salt content.

Based on temperature. Ocean currents can broadly be divided into two classes—the warm and the cold currents.

Warm and Cold Oceanic Currents

·Warm ocean currents originate near the equator and move towards the poles or higher latitudes while cold currents originate near the poles or higher latitudes and move towards the tropics or lower latitude.

1.The Warm Currents: These are those currents which flow from the low latitudes in Tropical Zones towards the high latitudes in the Temperate and Subpolar Zones. They bring warm water into cold water areas.

2.The Cold Currents: These currents have a lower surface temperature and bring cold water into warm water areas. These currents flow in the high latitudes from the Polar regions towards the low latitudes in the warm Equator region.

Oceanic Currents in Different Oceans

Pacific Ocean Currents

1-Equatorial Current (Warm)

2-North Equatorial Current (Warm): Flows across from east to west, i.e., from North America it reaches the Philippines.

3-South Equatorial Current (Warm): Peru Current eventually joins with the South Equatorial Current and completes the circuit.

4-Peruvian Current (Cold): Cold current near the west coast of S. America.

5-Kuroshio or Japan Current and W Winds drift (warm) Current (warm): N. Eq. current along the Philippines, Taiwan & Japan coast form this current. From the S.E. Japan the current, under the influence of prevailing westerlies, flows right across the ocean.

6-California Current (Cold): It moves southward along the coast of California

7-Oyashio or Kuril Current (Cold): Flows along the east coast of Kamchatka peninsula.

8-South Pacific Current: From west to east and crosses the Pacific Ocean along with the West Wind Drift.

9-East Australian Current (Warm): Flows from east to west in S. Pacific Ocean.

Indian Ocean Current

The currents in the N. Indian Ocean differ entirely from the general pattern of circulation. They change their direction from season to season in response to the seasonal rhythm of the monsoons.

1-Equatorial Centre Current (Warm)

2-South Equatorial Current (Warm)

3-Mozambique and Agulhas Current (Warm)

4-Monsoon Current (Warm)

5-South Indian Current (Cold)

6-West Australian Current (cold)

Atlantic Ocean Currents

1-Benguela Current (Cold): Cold current from S. to N near the ‘Cape of Good Hope’

2-South Atlantic Current (Cold)

3-Brazil Current (Warm): Flows along the S. American coast from North to South

4-Labrador Current (Cold): Flows along the eastern coast of Canada, meets the warm Gulf Stream near the north-east corner of U.S.A.

5-North Equatorial Current (Warm)

6-South Equatorial Current (Warm)

7-Gulf Stream (Warm): Beyond the Cape Hatteras up to the Grand Banks of New Found Land, Florida current is known as Gulf Stream. From the Grand Banks, the Gulf Stream moves eastward across the Atlantic as the Atlantic Drift.

8-Equatorial Counter Current or Guinea Current (Warm): Flows off the W. African coast

List of Surface Ocean Currents

Major Surface Ocean Currents

Name

Ocean

Type

Agulhas Current

Indian Ocean

Warm

Alaska Current

North Pacific Ocean

Warm

Benguela Current

South Atlantic Ocean

Warm/Cool

Brazil Current

South Atlantic Ocean

Warm

California Current

North Pacific Ocean

Cool

Canaries Current

North Atlantic Ocean

Cool

East Australian Current

South Pacific Ocean

Warm

Equatorial Current

Pacific Ocean

Warm

Gulf Stream

North Atlantic Ocean

Warm

Humboldt (Peru) Current

South Pacific Ocean

Cool

Kuroshio (Japan) Current

North Pacific Ocean

Warm

Labrador Current

North Atlantic Ocean

Cool

North Atlantic Drift

North Atlantic Ocean

Warm

North Pacific Drift

North Pacific Ocean

Warm

Oyashio (Kamchatka) Current

North Pacific Ocean

Cool

West Australian Current

Indian Ocean

Cool

West Wind Drift

South Pacific Ocean

Cool

Frequently asked questions:

What are the two types of currents in the ocean?

There are two type of Ocean Currents:

Surface Currents--Surface Circulation.

Deep Water Currents--Thermohaline Circulation.

Why is it important to know about ocean currents?

For the considerably longer periods– decades to millennia – which are relevant for climate change, the significantly larger heat capacity of the deep ocean is important. Ocean currents and mixing by winds and waves can transport and redistribute heat to deeper ocean layers.

What are the different ocean currents that carry warm water give at least three examples?

Western boundary currents are warm, deep, narrow, and fast flowing currents that form on the west side of ocean basins due to western intensification. They carry warm water from the tropics poleward. Examples include the Gulf Stream, theAgulhas Current, and the Kuroshio.

How ocean currents are generated?

Ocean currents can be generated by the wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes. Currents are cohesive streams of seawater that circulate through the ocean.

How does heat transfer causes ocean currents?

Ocean currents result from two processes - the action of the wind on the surface of the water, and from variation in water temperature that causes movement- a process known as convection. Convection occurs because the oceanic waters heat up becoming less dense.

How energy is transferred in the ocean?

The transfer of heat energy within the atmosphere, hydrosphere, and the Earth's surface and interior occurs as a result of radiation, convection, and conduction.Ocean currents play a significant role in transferring this heat toward the poles.

What causes the waves and tides?

Waves caused by underwater disturbances such as earthquakes, landslides, or volcanic eruptions are called tsunamis. These waves are typically tens to hundreds of kilometres long. The gravitational pull of the sun and moon on the earth causes the tides which are actually tidal waves.

How do geysers form?

As the water boils, the resulting pressure forces a superheated column of steam and water to the surface through the geyser's internal plumbing. The formation of geysers specifically requires the combination of three geologic conditions that are usually found in volcanic terrain